Diversity of biosurfactant producing microorganisms isolated from soils contaminated with diesel oil
| Autor: | William T. Frankenberger, Benedict C. Okeke, Fatima Menezes Bento, Flávio Anastácio de Oliveira Camargo |
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| Rok vydání: | 2005 |
| Předmět: |
Population
Bacillus cereus Bacillus Acinetobacter junii Polymerase Chain Reaction Microbiology Bacillus sphaericus California Surface-Active Agents Bioremediation Pseudomonas RNA Ribosomal 16S Soil Pollutants Food science education Soil Microbiology education.field_of_study Acinetobacter Bacteria biology Genetic Variation Sequence Analysis DNA biology.organism_classification Hydrocarbons Biodegradation Environmental Hong Kong Soil microbiology Fuel Oils |
| Zdroj: | Microbiological Research. 160:249-255 |
| ISSN: | 0944-5013 |
| Popis: | Biosurfactant production is a desirable property of hydrocarbon-degrading microorganisms (HDM). We characterized biosurfactant producing microbial populations from a Long Beach soil, California (USA) and a Hong Kong soil (China), contaminated with diesel oil. A total of 33 hydrocarbon-utilizing microorganisms were isolated from the soils. Twelve isolates and three defined consortia were tested for biosurfactant production and emulsification activity. The highest reduction of surface tension was achieved with a consortium of L1, L2 and L3 isolates from a Long Beach soil (41.4mN m(-1)). Isolate L1 (Acinetobacter junii) displayed the highest reduction of surface tension (46.5 mN m(-1)). The emulsifying capacity evaluated by the E24 emulsification index was highest in the culture of isolate L5 (74%). No substantial emulsification was achieved with the cell-free extracts, indicating that the emulsifying activity was not extracellular. Based on surface tension and the E24 index results, isolates F1, F2, F3, F4, L1, L2, L3 and L4 were identified by 16S rRNA gene sequencing as Bacillus cereus, Bacillus sphaericus, B. fusiformis, Acinetobacter junii, a non-cultured bacterium, Pseudomonas sp. and B. pumilus, respectively. Cluster analyses of 16S rRNA gene sequences of the bacterial isolates revealed 70% similarity amongst hydrocarbon-degrading bacterial community present in both soils. Five isolates (isolates F1, F2, F3, F4 and L4) belong to the Firmicutes order, two isolates (L1 and L3) belong to the Proteobacteria order and one isolate (L2) is an Actinomyces sp. Simpson's index (1 - D) and the Shannon-Weaver index (H) revealed more diversity of HDM in the Hong Kong soil, while evenness (E) and the equitability (J) data indicated that there was not a dominant population. Bacterial isolates displaying substantial potential for production of biosurfactants can be applied in the bioremediation of soils contaminated with petroleum hydrocarbons. |
| Databáze: | OpenAIRE |
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